Your tree may have a bagworm infestation. Bagworms cover themselves with plant parts and silk to protect themselves from predators. If you can reach the bags or cocoons, just pick them off and destroy them. When the worms are small you can spray them with Bt. You can try chemicals on the bags but they aren't as effective.

The cocoons on a pine tree will kill the tree. To get rid of the cocoons you can call a pest company and they will spray your trees and lawn. Or if you want to do it yourself you can buy insecticide spray and spray the trees and lawn yourself.

What apples are to an apple tree, cocoons ( also known as. pinecones ) are to a pine tree. It's just the pine tree's way of reproducing. For anyone not wishing to have to look at them, you could pick them off and dispose of them in your compost without hurting the tree, or simply just replant them